pgsql: Implement IF NOT EXIST for CREATE INDEX.

Implement IF NOT EXIST for CREATE INDEX.

Fabrízio de Royes Mello, reviewed by Marti Raudsepp, Adam Brightwell and me.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/08309aaf74ee879699165ec8a2d53e56f2d2e947

Modified Files
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doc/src/sgml/ref/create_index.sgml         |   14 +++++++++++++-
src/backend/catalog/index.c                |   17 ++++++++++++++++-
src/backend/catalog/toasting.c             |    2 +-
src/backend/commands/indexcmds.c           |    9 ++++++++-
src/backend/nodes/copyfuncs.c              |    1 +
src/backend/nodes/equalfuncs.c             |    1 +
src/backend/parser/gram.y                  |   26 ++++++++++++++++++++++++++
src/include/catalog/index.h                |    3 ++-
src/include/nodes/parsenodes.h             |    1 +
src/test/regress/expected/create_index.out |   10 ++++++++++
src/test/regress/sql/create_index.sql      |    6 ++++++
11 files changed, 85 insertions(+), 5 deletions(-)